Iran says it has filed a complaint against Russia at the International Criminal Court for failing to honour its agreement to deliver S300 rockets.

Mohammadreza Sajjadi, the Iranian Ambassador to Russia, told a press conference on Wednesday: "The agreement stipulates that if one of the two parties fails to stand by its commitments, the other may file a suit with the ICC."

He said a Russian official has told him that if the ICC rules that delivering the S300 rockets is not in violation of UN Security Council resolutions, then Russia will deliver them.

Sajjadi added: "We basically believe that the delivery of the S300 rockets is not against the resolution and, therefore, we filed a suit with the ICC so that Russia could find a way to gain the necessary legal permits to deliver the S300 rockets to Iran."

Iran signed the S300 rocket deal with Russia in 2005. According to the agreement, Russia was supposed to deliver five S300 missiles for $800 million. However, Russia has refused to honour the agreement, saying that it violates UN resolutions against Iran.

Iran's Revolutionary Guards responded to Russia's decision by announcing that its forces are in the process of designing "better missiles with greater capabilities."

The S300 missiles are top-of-the-line air defence systems used mainly to defend industrial areas and government and military bases.